The present invention relates to child resistant closures for containers having medicinals or other dangerous materials therein and, in particular, to such a container having a bipositional latch which allows adults of limited dexterity to easily open the container in one configuration and which provides a substantial amount of resistance to adolescents in opening the container when in the other configuration. Further, a hinge is provided which allows a closure member for the container to be molded separately from the remainder of the container, yet which prevents easy removal of the closure member from the hinge side when the closure member is closed. This allows a separately molded closure member to be easily mated with the container when the closure member is in an open position thereof.
For many years, both governmental and industry standards have been promulgated to attempt to prevent accidental poisoning or injury to children by making it relatively difficult for children to open certain types of containers, for example, pharmacy vials containing drugs. Unfortunately, most of the developments which make containers difficult to open by children also make the containers difficult to open by adults. This is especially true of adults having limited manual dexterity, such as both younger and older adults suffering from arthritis and other diseases or those having injuries which lessen the dexterity of the person.
Various prior art devices have been developed which attempt to provide both a difficult to open container when the product is being used in the presence of children and an easy open container for persons having limited dexterity. One such device of this type is described in applicant's U.S. Pat. No. 4,353,483 which included a bipositional hinged tab which made the lid easy to open when in one position and relatively difficult to open in another position.
Unfortunately, the prior art devices have had somewhat mixed success with children, since children can be quite creative in opening containers. This is especially true where a child is willing to use his or her teeth to attempt to open the lid of a container. The child is often able to make up for the loss of manual dexterity or the inability to understand how to open the lid through the strong pressure that can be exerted by the teeth and which can pry the lid open or bite off portions of the latch to allow the lid to open. Certain prior art devices have attempted to circumvent the problem of the child using the child's teeth to open the latch by the positioning of guard members to keep the child's teeth from engaging the lifting tab (for example, see the U.S. patent to Stull U.S. Pat. No. 3,826,394).
None of the prior art devices has highly effectively and inexpensively combined a structure which can be configured so that it is easy opening for adults and yet which can be configured so that it is very difficult to open by children.
It is also becoming increasingly evident to product safety specialists that closure members for certain types of containers, especially pharmaceutical vials, should be designed such that the lid once attached to the body is always maintained connected to the body of the container and preferably such that the lid can be closed using a single hand. That is, that a user can both swing the lid into a closed position while holding the vial with the same hand that is being utilized to swing the lid and that the lid will then automatically lock in a secured configuration when the lid is closed. This concept is frequently referred to as "one hand and one motion to close".
It is also desirable that the container include a hinge for connecting the lid to the body of the container that is also difficult for a child to manipulate and, thereby, open the container from the rear thereof. There is also a need in the industry for the lid to be able to be removed from the container when in the open configuration thereof such that the lid can be individually molded from the container. This allows one standard size lid to be manufactured for multiple sized containers or vials at a substantial savings in molding expense.
It is still further desirable that such a hinge hold the lid in at least one predetermined open position such that the lid will not flop freely back into a closed position, thereby making manipulation of the vial difficult.
It is also desirable to be able to provide covers or shields for both the latch and hinge to further prevent tampering with these structures by children using their teeth. In addition, the region between the container lid and body other than at the latch and hinge is preferably also protected from children prying apart the lid from the body in this region.
Finally, it is desirable in some instances to be able to provide a tamper indicating mechanism on the container which indicates that the lid has been previously opened. This is especially true of pharmaceuticals that are sold over the counter in order to alleviate concerns that the drugs therein have been poisoned.